The CFAR Pharmacology Core will support domestic and international research with the overarching goal of optimizing antiretroviral drug use. The Core will support innovative translational research of CFAR investigators. The complexity of HIV therapy, which includes the distinct characteristics of several classes of antiretroviral drugs, underscores the need for well designed state of the art pharmacology research. The Pharmacology Core and its Director have over 20 years of experience in HIV pharmacology research that stems back to when zidovudine was the only FDA approved drug for HIV-1 infection. The Core has three specific aims including: 1. Service through development and application of innovative or specialized pharmacological assays. The Core has extensive expertise in the development of novel assays for measuring drugs in cells and target tissues and for measuring the unbound fraction of highly bound drugs such as the HIV-1 protease inhibitors; 2. Research for domestic and international research with the goal of optimizing antiretroviral drug use. The Core will continue to design and implement pharmacokinetic and pharmacodynamic studies for a) distinct populations including women, pregnant women, children and those of specific ethnicities;b) novel drugs including CCR5 and integrase inhibitors, c) translational research aimed at determining which pharmacological factors predict outcomes, d) and drug-drug interaction studies relevant to domestic and international populations (i.e. for patients with malaria or tuberculosis); 3. Education and outreach through mentoring and training of junior clinical scientists in the area of HIV pharmacology research. The Core interacts with the International Core to optimize the training of students, fellows and post-graduate researchers interested in international research. The Core will also serve as a conduit for CFAR investigators to collaborate with other programs within the School of Pharmacy including the program on Pharmacogenetics of Membrane Transporters. The Core participates in rigorous QA/QC programs to ensure quality services. Assays within the Pharmacology Core include methods for most approved ARV drugs including intracellular methods for nucleoside analogues, plasma assays for non-nucleoside reverse transcriptase inhibitors and plasma, unbound and tissue assays for the protease inhibitors. Additional analytical methods are available for thalidomide and anti-CMV drugs